DESCRIPTION OF PROPOSED PROJECT: This is a collaborative effort among the Children's Research Institute and Hospital in Columbus, Cincinnati Children's Hospital, the Ohio Department of Health, and the University of Utah which is aimed at developing, evaluating, and implementing a laboratory protocol for newborn screening of creatine kinase (CK) on dried blood spots in relation to Duchenne Muscular Dystrophy (DMD). Validity of the screening test will be assessed and DMD status will be confirmed by DNA testing of the dystrophin gene. Investigators propose five aims to achieve the objectives. Aim 1 is to plan the activities with the CDC Scientific Liaison; Aim 2 is to develop laboratory protocols for CK testing and DNA analysis of dried blood spots using 12,000 anonymous neonatal male samples; Aim 3 is to develop, implement, and establish the informed consent for newborn screening for DMD; Aim 4 is to launch a feasibility project with another 12,000 subjects based on the results of Aims 1-3, and; Aim 5 is to implement a newborn screening of males for CK testing in a large population from the Great Lakes Regional Network (N>400,000).